Appendix A
3. Acronyms.
AC Advisory circular AGL Above ground level ARP Aerospace Recommended Practice ASTC Amended supplemental type certificate ATC Amended type certificate CCD Curser control device CFR Code of Federal Regulations COS Continued operational safety DO Document DOT Department of Transportation EFB Electronic flight bag FAA Federal Aviation Administration FMS Flight management system ICAO International Civil Aviation Organization MARPA Modification and Replacement Parts Association MG Minimum guidance NVG Night vision goggles NVIS Night vision imaging system PED Portable electronic device RGL Regulatory Guidance Library RTCA RTCA Inc.
RTCA/DO RTCA Inc. Document SAE SAE International STBY Standby STC Supplemental type certificate TC Type certificate A-2
Appendix B Appendix B. Control-Function Matrix
1. Introduction.
a. This appendix provides a brief description of a “control-function matrix”. It is not required for compliance, but can be helpful as a method for development, and for sharing data with the FAA.
b. A control-function matrix primarily maps control devices (e.g., knob) to control functions (e.g., change radio frequency). The matrix also provides for an organization of controls-related attributes, such as those addressed in this AC. It is a tool sometimes used by applicants to organize their design and compliance effort.
2. Table B-1. Table B-1 provides an example template of a control-function matrix.
The columns in table B-1 are described as follows:
a. Control: List each control separately in the table. Include traditional dedicated controls (e.g., knobs) and multifunction controls (e.g., software menus, touch-screen buttons) in the list.
b. Function Description Section: Group information that describes a function performed by a control in the matrix. In the table B-1 example, the function, criticality, frequency of use, and operational conditions are addressed.
(1) Function: Each function provided by a control is listed next to the name of the control. If a control provides multiple functions, list each function on a separate row, since the supplemental information may be quite different for each function.
(2) Criticality for Safety: This column provides relevant information about the criticality of a function from a system safety analysis. Criticality information can be helpful when considering implications associated with the possible inadvertent operation of a control (e.g., critical controls may need additional degrees of protection against inadvertent operation).
(3) Expected Frequency of Use: This column describes the frequency with which a function will be activated, deactivated, or manipulated. This information describes the function provided by the control. Frequency information can be helpful when considering the level of familiarity the pilot can be expected to have with a control, relative to its accessibility and complexity of operation (e.g., frequently used controls that are at the edge of a pilot’s reach envelope may not be compliant with 14 CFR 2x.777).
(4) Operational and Use Conditions: This column describes any operational use conditions that can impact the use of the control for that particular function. Operational and use conditions include those described in chapter 2, paragraph 2-2 of this AC, as well as flight phase. The information therefore establishes context in which the controls will be operated (e.g., functions that are regularly performed during final approach and B-1
Appendix B landing might need to employ a very simple method of operation to be compliant with 14 CFR 2x.771) and the acceptability of other features of the control’s design.
c. Design Description Section: Group information that describes the physical design of the control and its associated elements into the matrix. The table B-1 example groups information about methods of operation, labels, protection against inadvertent actuation, feedback from control actuation, and location of the control when installed.
(1) Method of Operation: Describe the method of operation for a function. A control that provides multiple functions could have the same method of operation for different functions, or it could have different methods of operation for different functions.
If a method of operation is difficult to describe in this matrix, it might also be difficult to perform for the pilot.
(2) Label: State the label associated with a function and method of operation.
This information is useful to ensure that all functions are labeled and there is no inappropriate use of the same label for different functions, or different labels for identical functions. If no label is provided, make an assessment to ensure that the control is “obvious.”
(3) Protection from Inadvertent Operation: This column captures descriptions of any design features that will prevent or reduce the likelihood of inadvertent operation of a function. This information might support compliance with 14 CFR 2x.777, requiring protection against inadvertent operation of controls.
(4) Feedback: This column captures information regarding feedback to the pilot during or following operation of a control.
(5) Location/Association: This column captures a description of the location of the control when installed. This information can be useful for understanding, for example, functional groupings and control-displays association.
d. Other Information Section: There may be several additional categories of information that are relevant to a function, the design of a control, factors that influenced the design decision process for the control, or the process of showing compliance. The table B-1 example uses a listing of related controls for each function, and a picture of the control.
B-2
Appendix B Table B-1. Example Template for Control-Function Matrix Control Function Description Design Description Other Information Function Criticality for Safety Expected Frequency of Use Operational and Use Conditions Method of Operation Label Protection from Inadvertent Operation Feedback Location/ Association Related Controls Picture(s) of Control [Name of Control, or Reference # in Diagram] [Name and Brief Description of Function #1] [e.g., Catastrophic Function, OR Major Function, OR Minor Function] [e.g., Multiple times per flight , OR Once per flight , OR Occasional use, OR Rarely used] [e.g., Control will be used during high workload phase of flight, in cold weather, in high vibration conditions] [Description of pilot actions required to perform Function #1] [Text of Label;
or “None”] [Description of design features that prevent inadvertent operation, or “None”] [Description of visual, aural, tactile, or other cues provided to indicate successful or unsuccessful operation of the control] [Position of control relative to the pilot upon installation]
(e.g., using a flight deck Zone reference) [List of Names or Reference #’s for other Controls associated with Function #1] [Name and Brief Description of Function #2] [e.g., Catastrophic Function, OR Major Function, OR Minor Function] [e.g., Multiple times per flight , OR Once per flight , OR Occasional use, OR Rarely used] [e.g., Control will be used during high workload phase of flight, in cold weather, in high vibration conditions] [Description of pilot actions required to perform Function #2] [Text of Label;
or “None”] [Description of design features that prevent inadvertent operation, or “None”] [Description of visual, aural, tactile, or other cues provided to indicate successful or unsuccessful operation of the control] [Position of control relative to the pilot upon installation]
(e.g., using a flight deck Zone reference) [List of Names or Reference #’s for other Controls associated with Function #2] B-3
Appendix C Appendix C. Regulations Table C-1 provides a quick reference to some 14 CFR regulations that address controls.
While many other regulations also apply to flight deck controls, as determined by the applicant’s regulatory basis, this AC focuses on the regulations in table C-1 because they are strongly related to human factors, and have often been subject to interpretation during aircraft certification projects. Table C-2 lists additional regulations that were cited in the AC.
Table C-1. Quick Reference to Regulations for Controls Related to Human Factors.
Key Aspect of Regulation, From a Human Factors Perspective (In some cases, wording may be paraphrased for clarity.
Consult regulations for exact wording.)
14 CFR Regulations Each control must operate with the ease, smoothness, and positiveness appropriate to its function.
23.671(a), 25.671(a), 27.671(a),
29.671(a) Controls must be located {part 23 only: arranged, and identified} to provide for convenience in operation.
23.671(b), 23.777(a), 25.777(a),
27.777(a), 29.777(a) Controls must be located {part 23 only: arranged, and identified} to prevent the possibility of confusion and subsequent inadvertent operation {part 29 only: from either pilot seat}.
23.671(b), 29.771(b), 23.777(a),
25.777(a), 27.777(a), 29.777(a) The pilot compartment must allow the pilot to perform his duties without unreasonable concentration or fatigue.
23.771(a), 25.771(a), 27.771(a),
29.771(a) The aircraft must be controllable with equal safety from either pilot seat.
25.771(c), 27.771(b), 29.771(b) Vibration and noise characteristics of cockpit equipment may not interfere with safe operation of the aircraft.
25.771(e), 27.771(c), 29.771(c) Controls must be identified (except where the function is obvious).
23.777(a) Controls must be located and arranged, with respect to the pilot seat, to provide full and unrestricted movement of each control without interference.
23.777(b), 25.777(c), 27.777(b),
29.777(b) A control must be of a kind and design appropriate to its intended function.
23.1301(a), 25.1301(a)(1),
27.1301(a), 29.1301(a) Controls must function properly when installed. 23.1301(d), 25.1301(a)(4),
27.1301(d), 29.1301(d) For alerting lights, installed in the cockpit, the color red must be used for warnings and the color amber for cautions.
23.1322, 27.1322, 29.1322 Use of the colors red, amber, and yellow on the flight 25.1322(e)(1), (f) C-1
Appendix C deck for functions other than flightcrew alerting must be limited and must not adversely affect flightcrew alerting.
Instrument lights must make each instrument and control easily readable and discernable.
23.1381(a) Instrument lights must make each instrument, switch, and other device, easily readable.
25.1381(a)(1), 27.1381(a),
29.1381(a) Instrument lights must be installed so that no objectionable reflections are visible to the pilot.
25.1381(a)(2)(ii), 27.1381(b)2,
29.1381(b)2 The minimum flightcrew must be able to access and easily operate controls required for safe operation.
23.1523, 25.1523, 27.1523,
29.1523 A cockpit control must be plainly marked as to its function and method of operation.
23.1555(a), 25.1555(a),
27.1555(a), 29.1555(a) Table C-2. Additional Cited Regulations General Topic 14 CFR Regulations Cockpit control knob shape. 25.781, 23.781 Instructions for continued airworthiness. 23. 1529, 25.1529. 27.1529,
29.1529 C-2